Question: Express your answer as a mixed number simplified to lowest terms. $17\dfrac{4}{5}-9\dfrac{1}{20} = {?}$
Solution: Separate the whole numbers from the fractional parts: $= {17} + {\dfrac{4}{5}} - {9} - {\dfrac{1}{20}}$ Bring the whole numbers together and the fractions together: $= {17} - {9} + {\dfrac{4}{5}} - {\dfrac{1}{20}}$ Subtract the whole numbers: $=8 + {\dfrac{4}{5}} - {\dfrac{1}{20}}$ Find a common denominator for the fractions: $= 8+\dfrac{16}{20}-\dfrac{1}{20}$ Subtract the fractions: $= 8+\dfrac{15}{20}$ Combine the whole and fractional parts into a mixed number: $= 8\dfrac{15}{20}$ Simplify to lowest terms: $= 8\dfrac{3}{4}$